Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 18, 2014 at 04:35 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update July 1, 2014)] [Cycle 24 progress (last update July 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update July 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update July 1, 2014)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update July 5, 2014)]

[POES auroral activity level October 2009 - December 2012]
[Solar polar fields vs solar cycles - updated July 18, 2014]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]

Recent activity

The geomagnetic field was very quiet on July 17. Solar wind speed at SOHO ranged between 352 and 404 km/s.

Solar flux at 20h UTC on 2.8 GHz was 88.6 (decreasing 13.6 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 136.8. The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.6). Three hour interval K indices: 11100111 (planetary), 11112222 (Boulder).

The background x-ray flux is at the class B1 level.

At the time of counting spots (see image time), spots were observed in 3 active regions using 2K resolution (SN: 40) and 3 active regions using 1K resolution (SN: 36) SDO images on the visible solar disk.

NOAA/SWPC observed no spots.

Spotted regions not numbered (or interpreted differently) by SWPC:
New region S3646 [N07W17] emerged early in the day and developed rudimentary penumbra on both polarities by the end of the day.
New region S3647 [N16W01] emerged with a penumbra spot.
New region S3648 [N11W09] emerged with a penumbra spot.

C2+ Flares (GOES):

Magnitude Peak time (UTC) Location AR
       

Coronal mass ejections (CMEs)

July 15-17: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.

Coronal holes

Coronal hole history (since October 2002)
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago

A recurrent southern hemisphere coronal hole (CH627) could rotate into an Earth facing position on July 20-21.

Coronal hole map

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle latitudes is fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet on July 18-21.

Coronal holes (1) Coronal mass ejection (2) M and X class flares (3)
     

1) Effects from a coronal hole could reach Earth within the next 5 days. When the high speed stream has arrived the color changes to green.
2) Effects from a CME are likely to be observed at Earth within 96 hours.
3) There is a possibility of either M or X class flares within the next 48 hours.

Green: 0-30% probability, Yellow: 30-70% probability, Red: 70-100% probability.

Active solar regions

(Click on image for 2K resolution) Compare to the previous day's image. 0.5K image

When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue is positive.

Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC. Comments are my own, as is the STAR spot count (spots observed at or inside a few hours before midnight) and data for regions not numbered by SWPC or where SWPC has observed no spots. SWPC active region numbers in the table below and in the active region map above are the historic SWPC/USAF numbers.

Active region Date numbered
detected
Spot count Location at midnight Area Classification SDO / HMI 4K continuum
image with magnetic polarity overlay
Comment
SWPC Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
12113 2014.07.06       N12W73          

plage

location: N08W68

SWPC moved AR 12113 to the location of spotless AR S3642

12114 2014.07.07
2014.07.08
      S19W56         plage

location: S19W50

12116 2014.07.08
2014.07.10
      S28W52           plage
S3631 2014.07.08       S15W55           plage
12117 2014.07.11       N09W65           plage
S3638 2014.07.13       N19W56           plage
S3640 2014.07.14       S19W25           plage
S3644 2014.07.15       S14E13         plage
S3645 2014.07.15       S32W40           plage
S3646 2014.07.17   8 4 N07W17 0030   DRO    
S3647 2014.07.17   1 1 N16W01 0003   AXX    
S3648 2014.07.17   1 1 N11W09 0003   AXX    
Total spot count: 0 10 6  
Sunspot number: 0 40 36  (total spot count + 10 * number of spotted regions)
Weighted SN: 0 13 9  (Sum of total spot count + classification weighting for each AR. Classification weighting: X=0, R=3, A/S=5, H/K=10)
Relative sunspot number (Wolf number): 0 14 20 k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for MSN 2K, k = 0.55 for MSN 1K (MSN=Magnetic Sunspot Number)

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number Average ap
(3)
Measured 1 AU
2013.02 104.3 101.8 38.0 58.4 (-0.3) 6.11
2013.03 111.3 110.2 57.9 57.5 (-0.9) 10.56
2013.04 124.8 125.9 72.4 57.9 (+0.4) 5.40
2013.05 131.4 134.3 78.7 59.9 (+2.0) 9.73
2013.06 110.1 113.7 52.5 62.6 (+2.7) 12.60
2013.07 115.5 119.3 57.0 65.5 (+2.9) 9.47
2013.08 114.6 118.3 66.0 69.0 (+3.5) 8.27
2013.09 102.6 103.7 36.9 73.1 (+4.1) 5.23
2013.10  132.1 131.2 85.6 75.0 (+1.9) 7.71
2013.11  148.3 145.1 77.6 75.4 (+0.4) 5.68
2013.12 147.7 143.1 90.3 76.0 (+0.6) 4.68
2014.01 157.4 152.4 81.8 (78.2 projected, +2.2) 5.44
2014.02 170.3
(cycle peak)
166.3 102.3 (cycle peak) (79.7 projected, +1.5) 10.70
2014.03 149.9 148.5 91.9 (80.5 projected, +0.8) 4.88
2014.04 143.9 144.8 84.7 (79.7 projected, -0.8) 7.88
2014.05 129.7 132.9 75.2 (77.1 projected, -2.6) 5.75
2014.06 122.0 125.8 71.0 (74.5 projected, -2.6) 6.72
2014.07 157.9 (1)   78.9 (2A) / 143.9 (2B) / 87.9 (2C) (71.5 projected, -3.0) (4.8)

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
2A) Current impact on the monthly sunspot number based on the Boulder (NOAA/SWPC) sunspot number (accumulated daily sunspots / month days). The official WDC-SILSO international sunspot number is typically 30-50% lower. 2B) Boulder SN current month average to date. 2C) STAR SDO 1K Wolf number 30 day average.
3) Running average based on the quicklook and definitive Potsdam WDC ap indices. Values in red are based on the definitive international GFZ Potsdam WDC ap indices.

This report has been prepared by Jan Alvestad. It is based on the analysis of data from whatever sources are available at the time the report is prepared. All time references are to the UTC day. Comments and suggestions are always welcome.

SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.